Fast lighting charcoal briquet

ABSTRACT

Solid fuel briquets, such as a charcoal briquets for cooking, which displays an ashover time of less than ten minutes and a cooking time of over 90 minutes over a variety of shapes are provided. The briquet is defined by an ashover phase of less than about 10 minutes, preferably less than about 6 minutes and a burn phase of greater than about 90 minutes, preferably two hours and above, with respect to any desired briquet shape. The briquet comprises coal, charcoal, coke, and oxidizer formulations.

This application claims the benefit of U.S. Provisional Application No. 60/640,853, filed on Jan. 3, 2005 which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

This invention relates to the field of charcoal briquets and other solid fuel compositions in briquets or other geometric configurations, and more particularly to the composition and use of the briquets to achieve desired lighting and burn characteristics with respect to intended uses such as cooking in general and barbecue or outdoor grilling or cooking in particular. The most common examples of such fuel compositions are charcoal briquets which include coal and comminuted charcoal of various vegetable materials, such as wood, hulls, pits, and other agricultural waste material that is mixed with a binder and rolled, pressed or otherwise formed into briquets. However, the present invention has application to other solid fuel compositions, such as comminuted wood or organic materials that are rolled, pressed or extruded into pellets, discs, briquets or other shapes.

Charcoal briquets presently available are typically provided in a “pillow” shape which provides for reasonably satisfactory ease of manufacturing by the supplier and handling by the consumer. However, little attention has been paid to their burning characteristics as related to their material distribution. As is well known, such briquets are typically used for cooking on a grill or the like by preparing a multiplicity of briquets in a mounded configuration, igniting their surface by some ignition means such as lighter fluid, electric heaters, etc., and waiting until ignition of a significant portion of the briquets has progressed until a majority of the exposed surface is ignited and burning has progressed inwardly toward the interior of the briquet. As burning proceeds inwardly from the surface of the briquet, a gray ash is formed thereon. Thus completion of the initial “ignition phase” of burning is identifiable by the formation of such visual ash on the briquet, and is defined herein as the time at which there is 60-80% visual ash formation on the briquets. This has been referred to by some as “ashover” time. Thereafter the briquets are typically spread under a grill or the like for cooking, and they continue to burn with an intense heat throughout a “burn phase” or cook time. For maximum performance of such briquets it is desirable that the ignition phase be rapid so that the briquets may be used for cooking without undue delay, and that the burn phase be extended to provide adequate cooking time for the use intended. It is further desirable to obtain such beneficial combustion performance in the most efficient manner with respect to the amount of fuel consumed.

As can be seen, the desired effects are rapid “ashover” periods with extended cooking times. There have been little developments related to design of solid fuel articles for desired combustion performance. There has been some work at ornamental configuration of fuel briquets, as well as geometrical configuration of briquets to enhance ignition or burning by enhancing air supply, such as provision of external surface discontinuities such as ribs, flutes, groups, slots or the like, and internal openings and passages of various configurations. Such attempts may enhance commencement of ignition or overall combustion, but do not provide desired optimal ignition and burning characteristics. Further, such attempts are frequently dependent on the user's knowledge of how to pile the briquets before ignition.

It should be noted that very rapid delivery of intense heat does not provide an acceptable combustion response for cooking purposes. Others have recognized that the surface area to volume ratio of the briquet may affect ignition and burn characteristics and should be increased to provide rapid ignition and burning. However, such ratios have not been employed to design a briquet providing optimal desired ignition and burning characteristics. Layered briquets, having an easy lighting outer layer and long burning inner layer have been disclosed, but can not be commercially manufactured without loss of layer integrity.

For example, U.S. Pat. No. 5,762,656 provides for a solid fuel briquet, such as a charcoal briquet for cooking, where the briquet is made by predensifying a coal portion of the briquet into pellets. The pellets are then blended with wood charcoal and any other optional ingredients and compacted into briquets. The resulting briquet contains dense coal regions, surrounded by regions of charcoal and any adjunct briquet ingredients. The briquet is defined by an ignition phase of less than about 18 minutes, preferably less than about 15 minutes and a burn phase of greater than about 35 minutes, preferably 40 minutes and most preferably 45 minutes, with respect to any desired briquet shape.

Accordingly, it is an object of the present invention to provide a briquet which provides desired ignition and burn phase characteristics including a maximum ignition phase of less than about 10 minutes, followed by a sustained burn phase of greater than 90 minutes.

Another object of the present invention is to provide such a briquet with desired ignition and burn phase characteristics regardless of geometric shape, size, or other manufacturing parameters.

Another object of the invention is to provide a briquet having an “ashover” time of less than six minutes.

Another object of the invention is to provide a briquet having a sustained burn phase or cook phase of over about two hours.

Other objects of the invention will be clear from the summary and detailed description appearing herein.

SUMMARY

The present invention provides a solid fuel briquet for cooking, such as a charcoal briquet, which displays selected ignition and burn characteristics over a variety of shapes and compositions, as well as a method for forming such a briquet. In accordance with one embodiment, the present invention provides briquets or other solid fuel composition for cooking, comprising: coal, charcoal, and oxidizer, wherein the briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes. The briquet optionally comprise coke. The coke provides various properties including increased cooking time. The briquets have an ashover time of less than six minutes. Preferably, the briquets have an ashover time of less than five minutes. Most preferably, the briquets have a starting time of less than one minute, and ashover time of less than five minutes and a cooking time of over two hours.

In accordance with one embodiment of the present invention, the briquets comprise coal, charcoal and coke with a combined weight representing from 55 to 85 percent of the total weight of the briquet. The coal represents from 50 to 75 percent of the combined weight. The coke is present in an amount of 2-5 percent of the combined weight. The oxidizer represents at least fifteen percent of at least one alkali metal nitrate composition. When reference is made to a metal nitrate, this includes composition including such a nitrate or combinations therewith. In a preferred embodiment the oxidizer comprises at least two alkali metal nitrates and is present in an amount of twenty percent or higher by weight of the total briquet composition.

In accordance with one embodiment, the present invention provides briquets or other solid fuel composition for cooking, where the briquets comprise coal having a fixed carbon of 65 percent or more, charcoal, and coke. The briquets further comprise an oxidizer composition comprising at least two different alkali metal nitrates. Such briquets are characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes. The coal, charcoal and coke have a combined weight representing from 55 to 85 percent of the total weight of the briquette or briquets. The coal represents from 50 to 75 percent of the combined weight, and the coke is present in an amount of 2-5 percent of the combined weight. The oxidizer represents at least fifteen percent. In various variations of this embodiment, the oxidizer composition comprises a first alkali metal nitrate which is selected from the group consisting of strontium nitrates, barium nitrates, higher molecular weight metal nitrates and combinations thereof. By higher molecular weight nitrates, we mean those alkali (including earth) metals having a higher molecular weight than strontium. The oxidizer composition further comprises a second alkali metal nitrate selected from the group consisting of sodium nitrates, potassium nitrates, lower molecular weight alkali (including earth) metal nitrates and combinations thereof. By lower molecular weight alkali metal we mean those having a lower molecular weight than calcium. In a preferred embodiment, the first alkali nitrate is present in greater amounts than the second alkali metal nitrate. In yet another embodiment, the oxidizer is present in amounts equal to or greater than twenty percent. In yet another embodiment, the oxidizer is present in amounts equal to or greater than twenty five percent. In yet another embodiment, the oxidizer is present in amounts equal to or greater than thirty percent.

In another embodiment, the present invention teaches a briquette, briquets or other solid fuel compositions, comprising coal having a fixed carbon of 65 percent or more, charcoal, and coke. The coal, charcoal and coke have a combined weight representing from 55 to 90 percent of the total weight of the briquette or briquets. The coal represents from 50 to 75 percent of the combined weight. The coke is present in an amount of 2-5 percent of the combined weight. The oxidizer composition is at least ten percent of at least one alkali metal nitrate. The briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes.

In another embodiment, the present invention provides briquet or other solid fuel composition system for cooking, comprising briquets comprising coal, charcoal, coke and two alkali metal nitrates. In addition to the briquets, an alcohol based gel ignition aid is provided. When the get system is used, the briquets have a starting time of less than one minute, an ashover time of less than five minutes and a cooking time of more than two hours.

In another embodiment, the present invention provides a briquet or other solid fuel composition, comprising (a) from 35 to 45 percent by weight coal having a fixed carbon of 65 percent or more, (b) from 16 to 20 percent by weight charcoal, (c) from 4 to 6 percent by weight by weight coke, (d) from 25 to 30 percent by weight barium nitrate, (e) from 4 to 6 percent by weight sodium nitrate, and (f) from 3 to 5 percent by weight starch.

DETAILED DESCRIPTION

In this document, use shall be made of the following terms of art, which have the meanings as indicated below.

The term “Binder” as used herein refers to complex carbohydrates that possess adhesive qualities to produce or promote the holding together of loosely aggregated components as in a briquet. Examples of binders include starches such as corn starch.

“Coal” as used herein refers to a solid combustible substance formed by the partial decomposition of vegetable matter without free access of air and under the influence of moisture and often increased pressure and temperature that is widely used as a natural fuel. It is further understood that coal includes substances such as the foregoing either before or after partial burning and/or scorching in an oxygen-poor environment (or charring) such as might be carried out to remove undesirable components, an example of which is sulfur. It is therefore understood that designations such as lignite and lignite charcoal, anthracite, semi-anthracite, bitumen, mineral carbons and mixtures of any of the foregoing, as well as any partially burned or scorched portions thereof, may singularly or collectively be referred to herein as coal.

The term “Ignition Aid” as used herein refers to materials that are useful in the act or process of initiating the oxidation or combustion of a fiel mixture or mixture of other objects, such as one or more briquets. Examples of ignition aids that are consistent with the meaning of this term as used herein include sawdust and other particulate cellulosic matter as well as mixtures thereof, solvents such as aliphatic and petroleum hydrocarbons and blends thereof, and starter gels such as burning alcohol gels.

“Optional adjuncts” as used herein refers to components which may be desirably included in a briquet formulation to enhance appearance or aesthetic use qualities thereof. Examples of optional adjuncts include: builders; fillers; density modifiers; ash whiteness enhancers; release agents, etc., as well as combinations of any of the foregoing. A typical builder includes limestone, and borax as well as various hydrates of the boron oxides can be used for dual purposes as release agents and/or builders. Limestone and borax decahydrate are preferred optional adjuncts.

As used herein, the term “Oxidizer” is understood to refer to any material or component which can effectively increase the supply of oxygen to combustible ingredients of the formulation. Alkali metal nitrates (including alkali earth metals) are examples of preferred oxidizers. Sodium, potassium, barium and strontium nitrates are preferred oxidizers in accordance with various embodiments of the present invention.

The term “Wood Charcoal” or “Charcoal” as used herein refers to the hard fibrous substance consisting basically of xylem that makes up the greater part of the stems, branches and roots of trees or shrubs beneath the bark and is found to a limited extent in herbaceous plants and which has been partially burned or scorched or otherwise converted to carbon to some extent. Wood charcoal or charcoal is a comprehensive term and includes retort charcoals, kiln charcoals, and the like.

Charcoal briquets and the like are employed by leaving a multiplicity of briquets initially mounded into a pile for better ignition. The combustion of such briquets is resolvable into an initial “ignition” phase which begins with the commencement of ignition and proceeds until the briquets are ignited over substantially their entire surface, and a “burn” phase in which combustion continues to proceed from the exterior surface of the briquet to the interior. At this time there is a significant rise in the temperature and heat generated by the burning briquets. This transition from the ignition phase to the burning phase can be usually identified by a layer of gray ash which forms on the surface of the briquet after initial burning at the surface.

For purposes of illustrating the present invention, the process for cooking with briquets will be divided into various phases. The first phase is the starting or ignition time and represents the time when ignition aids such as lighter fluid, petroleum distillates, starting gel etc. are applied to the briquets and then lighted, to the time the briquets start to burn on their own without any further application of ignition aids. This definition only refers to the portion of briquets that have been given ignition aids, not the briquets that have not been given ignition aids. The ignition phase is followed by an ashover phase. The end of the ashover phase is defined as the time, in minutes, at which a majority of the surface of the briquets display a visual ash. As understood herein, the time required to achieve a certain amount of visual ash cover is regarded as the “ashover time”. The amount of ash that has been found to be a convenient tool for evaluation purposes, expressed as a percent of total briquet surface area, is approximately 60-90% visual ashover, and more preferably 70-80% visual ashover. These values may be written as 60-90% ashover and 70-80% ashover, respectively. The length of time which has been found to be convenient for use in evaluating the ash appearance on briquets is approximately 5-20 minutes following ignition, and preferably 10-15 minutes following ignition. According to one preferred embodiment of the present invention, it is desired that 70% ashover occurs within less than about 10 minutes, and preferably less than about 6 minutes. Most preferably, the ashover time or 70-80 percent ashover occurs in less than five minutes. It is to be understood that size, weight and composition can all influence ignition and burn phase characteristics of briquets. One prior technique for optimizing burn characteristics based on shape configuration has already been described in U.S. Pat. No. 4,496,366 to Peters, and is incorporated by reference herein. Thus, for purposes of providing a convenient and relatively consistent basis for comparison, briquets that were evaluated in the course of the present invention were approximately pillow-shaped in configuration, and had an average weight of approximately 40 g. It is to be understood that the technique of the present invention can also be employed to design charcoal briquets with other ignition and performance characteristics, if so desired.

Upon completion of an initial ignition and ashover phases, briquets are normally spread out upon a planar surface beneath a grill or other cooking surface or the like. During the subsequent burn phase, the briquets continue to burn with an intense heat for a period of time, during which they are employed for purposes such as cooking or the like. The total amount of time, in minutes, where the briquets are useful for cooking can be rather arbitrary, as they can vary depending upon the subjective temperature range and/or the degree of “doneness” desired for a food item, the nature of the item being cooked, etc. Consequently, it is convenient to select a temperature to be used in determining cooking time values. In general, the temperature range over which cooking with briquets is most commonly associated varies from about 135 degree Centigrade (C) (275.degree. F.) for rare or raw cooking to about 250 degree C. (approx. 480 degree F.) for well-done cooking. Thus, for comparison purposes, the present invention evaluates the cooking time as the time above 400 degree F. It should be understood that this value is for comparison of the performance of the various formulations and not as the actual cooking time that may be employed by the ultimate user.

An important aspect of briquet performance is the amount of time for which the burn phase configuration or composition can sustain a cooking temperature, i.e., the time available for cooking, or “cook time.” A briquet that ignited readily and gave rise to short ash times, for instance, would be desirable in that cooking could conveniently commence relatively quickly following ignition. However, if such a briquet was to become consumed too rapidly, it would not be acceptable for providing a fuel source for sustained cooking. Therefore the “cook time” associated with a briquet is defined for the purposes herein as the time the briquet generates heat over 400 degree F. According to one preferred embodiment of the present invention, it is desired that CT have values comprising a minimum of 90, preferably 120, and more preferably over 120 minutes.

Briquets are typically predominantly comprised of two components: wood charcoal, which is relatively easy to ignite but combusts rapidly, and coal, which is more difficult to ignite and burns more slowly than wood charcoal, but which also burns at higher temperatures. Wood charcoal is produced either in concrete kilns or retort furnaces where wood is placed and a portion of the wood is burned in an atmosphere that is made deficient in available oxygen by restricting the airflow. The reduced oxygen atmosphere prevents complete combustion of the wood, allowing the production of charcoal which has been depleted of the more volatile materials (which cause smoke) but which still contain most of the carbon, which provides one of the cooking sources for the briquets.

In accordance with one aspect of the invention, wood charcoal is combined with coal, binders and other components. The latter comprise ignition aids and/or optional adjuncts, which may include some or all of the following: sawdust, alkali metal nitrates, fillers, density modifiers, ash whiteness enhancers and solvents, etc. These ingredients are blended together and then mixed in a large mixer with a cooked and thickened binder, such as a starch slurry, which acts to hold all of the other materials together. The mixture is then formed into the desired shape by rolling, extruding, pressing, etc. In a typical rolling process, the mixture is fed into a large roll press in which two large rotating shafts having drum cylinders with pockets on them squeeze the material into briquets of a configuration that is determined by the shape of the pockets. These briquets are then dried in large tunnel dryers where they are piled on large perforated wire belts and hot air is blown through the belts and briquets to dry off excess moisture that was added in the starch slurry. This step hardens the starch binder so that the briquets achieve a higher strength to enable them to be handled, packaged and shipped. The briquets are then packaged in standard bag filling equipment. In accordance with a preferred embodiment of the present invention, the briquets are package in a box with a plastic liner to seal any particles or dust that may have separated from the briquets during shipping or handling. The plastic liner also serves to protect the briquets from exposure to moisture which adversely affects the performance of the briquets such as starting or ignition and ashover times.

In making briquets in accordance with the present invention, the following materials are utilized. Various formulations of potassium nitrates, barium nitrates, sodium nitrates and strontium nitrates are preferably used as the oxidizers in the briquets. Potassium nitrate seemed to provide too much sparking when used in large quantities and this is less desirable from a consumer point of view and not from a performance point of view. Strontium nitrates are more desirable but are presently the more expensive of the other nitrates. The nitrates are in either powder or crystal forms and have purities in the range of 95 percent or higher, with purities of 99 percent or higher being preferred. We have also found it advantageous to use a combination of at least two nitrates. This provided improved results in the performance of the briquets. Based on the overall weight of the briquets, the following combinations are used in various embodiments of the invention (a) strontium nitrates (15-35%) plus sodium nitrates (5-10%); (b) strontium nitrates (15-35%) plus potassium nitrates (5-10%); (c) barium nitrates (15-35%) plus sodium nitrates (5-10%); (d) barium nitrates (15-35%) plus potassium nitrates (5-10%); or (e) barium nitrates (15-35%) plus sodium nitrates (2.5-5%) plus potassium nitrates (2.5-5%). Various other combinations are possible for use in various embodiments of the present invention. In accordance with the desired properties of the briquets relative to ashover time and cook time, the amount of the nitrate oxidizers used was at least 10% by weight of the briquette, preferably at least 20% by weight, and most preferably over 25% by weight. In accordance with various embodiments of the present invention using at least two different nitrates, strontium nitrates and barium nitrates represent the major portion of the oxidizer content while sodium nitrates and potassium nitrates represent minor portions. Preferred nitrates include sodium nitrate, potassium nitrate, barium nitrate and strontium nitrate.

The coke utilized is known in the art and readily available from various sources. It is advantageous to use coke having a higher fixed carbon value. Preferred coke has a fixed carbon content of at least 65% and most preferred is coke having a fixed carbon content of 80% or higher. In one production, the coke had a fixed carbon content of over 80%, less than 12% ash, less than 0.6% sulfur, less than 0.04% phosphate, less than 4% water (or moisture), and approximately 1.5% volatile matter. The higher fixed carbon cokes result in better burning and improved cook times. The coke is used in smaller amounts as compared to the coal and charcoal.

The coal used in the present invention is preferably the type with a high fixed carbon value such as 65% or higher. This provides longer burning time or cook time. The coal preferably also has a high gross calorie value or calorific value, preferably 6,000 kcal/kg or higher (kilo calories per kilogram). The coal used in the last production batch had a gross calorie value of 6,500 kcal/kg or higher. It also preferred to use coal of low sulfur content to minimize emissions and odor. A sulfur content of less than one percent is preferred. Anthracite is a preferred coal type and is used in various embodiments of the present invention because it is cleaner. Bituminous coal is less desirable because it produces more smoke and other undesirable gaseous emission.

With respect to the charcoal, we have determined that the higher fixed carbon content charcoals perform better in various embodiments. We have also found that hardwood charcoals performed better than others in various embodiments. Wood charcoal can also be substituted by carbon content derived from saw dust, nut shells, or other plant based carbon. These preferences are not intended as limitations and the selection should be made based on the desired ashover and cook times.

The proportions of coal to wood charcoal can be varied to achieve different goals of heat value and starting times. Coke is optionally added as an ingredient to improve cooking time values. We have found that the presence of coke allows for longer cooking time values, such as over two hours. All of the examples showing cooking time of over two hours includes coke with the coal and wood charcoal. In various embodiments, the combined weight of coke, coal and charcoal in the briquets can vary between 55 to 90 percent by weight. The distribution within this range between the products is such that the coal represents 50 to 75 percent of the combined weight, the coke represents from 2 to 15 percent of the combined weight and the charcoal makes up the remainder. It is preferred that the combined weight is from 55 to 80 percent and most preferred between 55 to 75 percent.

Binders and other material may be used to assist in holding the briquets together. For example, starch is used in various embodiments of the invention as a binder for the manufacture of the briquets. While starch is preferred, various other known binders can be used.

Ignition aids can be used to assist in the starting of the briquets of the present invention. It was found that the use of gels, such as burning alcohol gels is preferable. These gels provide very discrete and more controlled burning on the briquets. Further, the present invention briquets need a minimal amount of these gels to assist in the starting phase. For example, these gels comprise approximately 90% burning alcohol and approximately 10% coagulant (to turn liquid alcohol to a gel form). In a preferred embodiment, a small tube of such a gel starter material is provided in a box containing the briquets of the present invention. For example, a bottle of gel of about 25 grams is provided and is recommended for about three uses. The average use of briquets is about two to three pounds. Another unique feature of our charcoal briquet is that, you need only to apply starting gel to a fraction of the charcoal pile. When that portion of the briquets has been ignited (in less than one minute) the fire quickly spreads to the whole pile. A 3-5 Lb pile of briquets will ashover in less than 5 minutes.

The above ingredients were utilized to form briquets in accordance with various embodiments of the present invention. Methods of forming the briquets are known in the art. In one batch of briquets, the following formulation was used: approximately 40% by weight coal; approximately 18% wood charcoal; approximately 5% coke; approximately 28% barium nitrate; approximately 5% sodium nitrate; and about 4% corn starch (including moisture therein). Various other batches were made with similar compositions within the scope of the invention. These batches were subjected to quality control tests including ashover time and cook time requirements. The testing included inspection for workmanship, physical and chemical properties, and performance properties. The workmanship tests included visual inspection of the briquets to compare to the criteria of no cracks, visible wood, missing chunks, pits nor foreign material in the briquets. The briquets were also tested to meet the criteria of no strong odor. For the physical and chemical properties testing, ASTMD 1762 was used to test for percent moisture and percent ash in the briquets. The ash content was tested on a before and after weight comparison.

The performance tests included tests for the ease of ignition, ashover time and cooking time. The target was that the briquets should ignite within five minutes if proper lighting instructions were followed. Ashover tests results were also reported by visual inspection with the time reported for 100% ashover. It should be noted that this criteria is more restrictive than those previously used. Normally 75 to 80 percent ashover time is considered sufficient for comparison purposes. The burn test results were reported as time over 400 degree F. The target for the burn test was about two hours or more above 400 F. Smoke generation was visually noted and the target criteria was a subjective requirement that no excessive smoke be generated during the burn phase. Smoke is observed during the ignition phase. The data is reported below for the various batches tested. The tests were performed using one kilogram samples (2.2 pounds) and using the starting gel as an ignition aid. TABLE I Evaluation A B C D A. Construction workmanship 1. Defects Conform to Conform to Conform to Conform to requirements requirements requirements requirements 2. Odor No strong odor No strong odor No strong odor No strong odor B. Physical/Chemical Property 1. Percent <5.0%   <4.0%   <4.0%    5.0% Moisture 2. Percent Ash  29%  26%  27% 31.5% C. Performance 1. Ease of ignition <1 Min.    <1 Min.  <1 Min. Appr. 1 Min. 2. Ashover time <3 Min.   3-4 Min.  <4 Min. 3-4 Mins. 3. Time above 160 Min.  165 Min. 158 Min. 165 Mins. 400 F. 4. Smoke No excessive No excessive No excessive No excessive smoke smoke smoke smoke

As can be seen from the data, the briquets made in accordance with various embodiments of the present invention exhibited improved properties as compared to those presently available on the market. The moisture content was not greater than 5.0 percent for all batches with most being below 4 percent. The ignition time was one minute or less for all batches. Starting or ignition time is the time it takes to get the briquets to burn on their own without any ignition aids such as alcohol gel or lighter fluid. It is basically after the lighter fluid, gel or petroleum distillates, in the case of match light or similar products, have burnt out and the briquets started to catch fire and burn on their own content.

The ashover time for all reported samples was less than four minutes. The target was less than ten minutes and most preferably less than five minutes. This represents a significant improvement over the presently available briquets. The cook time or time over 400 F was in excess of two hours and about 2.5 hours or more for the batches shown in Table I. Even having a burn time or cook time of about ninety minutes to two hours represents a significant improvement over what has been reported for similar products presently available.

It was also determined that the briquets of the present invention hold their form after burning. After burning, the briquets retain their shape to a larger degree than expected with minimal deformation or loss as ash. However, when subjected to force, the burnt or used briquets easily lose their form.

In accordance with one embodiment, the present invention provides briquets or other solid fuel composition for cooking, comprising: coal, charcoal, and oxidizer, wherein the briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes. The briquet optionally comprise coke. The coke provides various properties including increased cooking time. The briquets have an ashover time of less than six minutes. Preferably, the briquets have an ashover time of less than five minutes. Most preferably, the briquets have a starting time of less than one minute, and ashover time of less than five minutes and a cooking time of over two hours.

In accordance with one embodiment of the present invention, the briquets comprise coal, charcoal and coke with a combined weight representing from 55 to 85 percent of the total weight of the briquet. The coal represents from 50 to 75 percent of the combined weight. The coke is present in an amount of 2-5 percent of the combined weight. The oxidizer represents at least fifteen percent of at least one alkali metal nitrate composition. When reference is made to a metal nitrate, this includes composition including such a nitrate or combinations therewith. In a preferred embodiment the oxidizer comprises at least two alkali metal nitrates and is present in an amount of twenty percent or higher by weight of the total briquet composition.

In accordance with one embodiment, the present invention provides briquets or other solid fuel composition for cooking, where the briquets comprise coal having a fixed carbon of 65 percent or more, charcoal, and coke. The briquets further comprise an oxidizer composition comprising at least two different alkali metal nitrates. Such briquets are characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes. The coal, charcoal and coke have a combined weight representing from 55 to 85 percent of the total weight of the briquette or briquets. The coal represents from 50 to 75 percent of the combined weight, and the coke is present in an amount of 2-5 percent of the combined weight. The oxidizer represents at least fifteen percent. In various variations of this embodiment, the oxidizer composition comprises a first alkali metal nitrate which is selected from the group consisting of strontium nitrates, barium nitrates, higher molecular weight metal nitrates and combinations thereof. By higher molecular weight nitrates, we mean those alkali (including earth) metals having a higher molecular weight than strontium. The oxidizer composition further comprises a second alkali metal nitrate selected from the group consisting of sodium nitrates, potassium nitrates, lower molecular weight alkali (including earth) metal nitrates and combinations thereof. By lower molecular weight alkali metal we mean those having a lower molecular weight than calcium. In a preferred embodiment, the first alkali nitrate is present in greater amounts than the second alkali metal nitrate. In yet another embodiment, the oxidizer is present in amounts equal to or greater than twenty percent. In yet another embodiment, the oxidizer is present in amounts equal to or greater than twenty five percent. In yet another embodiment, the oxidizer is present in amounts equal to or greater than thirty percent.

In another embodiment, the present invention teaches a briquette, briquets or other solid fuel compositions, comprising coal having a fixed carbon of 65 percent or more, charcoal, and coke. The coal, charcoal and coke have a combined weight representing from 55 to 90 percent of the total weight of the briquette or briquets. The coal represents from 50 to 75 percent of the combined weight. The coke is present in an amount of 2-5 percent of the combined weight. The oxidizer composition is at least ten percent of at least one alkali metal nitrate. The briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes.

In another embodiment, the present invention provides briquet or other solid fuel composition system for cooking, comprising briquets comprising coal, charcoal, coke and two alkali metal nitrates. In addition to the briquets, an alcohol based gel ignition aid is provided. When the get system is used, the briquets have an ignition time of less than one minute, an ashover time of less than five minutes and a cooking time of more than two hours.

In another embodiment, the present invention provides a briquet or other solid fuel composition, comprising (a) from 35 to 45 percent by weight coal having a fixed carbon of 65 percent or more, (b) from 16 to 20 percent by weight charcoal, (c) from 4 to 6 percent by weight by weight coke, (d) from 25 to 30 percent by weight barium nitrate, (e) from 4 to 6 percent by weight sodium nitrate, and (f) from 3 to 5 percent by weight starch.

Although the present invention has been described in terms of specific embodiments, various substitutions of materials and conditions can be made as will be known to those skilled in the art. For example, the other material could be substituted for the starch in order to provide adhesion or structure strength for the briquets. Other variations will be apparent to those skilled in the art and are meant to be included herein. The scope of the invention is only to be limited by the following claims: 

1. A briquet or other solid fuel composition for cooking, comprising: coal, charcoal, and oxidizer, wherein the briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes.
 2. The briquet of claim 1 further comprising coke.
 3. The briquet of claim 1 having an ashover time of less than six minutes.
 4. The briquet of claim 1 having an ashover time of less than five minutes.
 5. The briquet of claim 2 having a cooking time of over two hours.
 6. The briquet of claim 2 having an ashover time of less than five minutes and a cooking time of over two hours.
 7. The briquet of claim 2 wherein the coal, charcoal and coke have a combined weight representing from 55 to 85 percent of the total weight of the briquet; and where the coal represents from 50 to 75 percent of the combined weight; and the coke is present in an amount of 2-5 percent of the combined weight; and wherein the oxidizer represents at least fifteen percent of at least one alkali metal nitrate.
 8. The briquet of claim 1 wherein the oxidizer comprises at least two alkali metal nitrates and is present in an amount of twenty percent or higher by weight of the total briquet composition.
 9. A briquet or other solid fuel composition for cooking, comprising: coal having a fixed carbon of 65 percent or more; charcoal; coke; and oxidizer comprising at least two different alkali metal nitrates; wherein the briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes.
 10. The briquet of claim 9 wherein the coal, charcoal and coke have a combined weight representing from 55 to 85 percent of the total weight of the briquet; and where the coal represents from 50 to 75 percent of the combined weight; and the coke is present in an amount of 2-5 percent of the combined weight; and wherein the oxidizer represents at least fifteen percent.
 11. The briquet of claim 9 wherein a first alkali metal nitrate is selected from the group consisting of strontium and barium nitrates and combinations thereof, and wherein a second alkali metal nitrate is selected from the group consisting of sodium and potassium nitrates and combinations thereof.
 12. The briquet of claim 9 wherein the first alkali nitrate is present in greater amounts than the second alkali metal nitrate.
 13. The briquette of claim 9 wherein the oxidizer is present in amounts equal to or greater than twenty percent.
 14. The briquette of claim 9 wherein the oxidizer is present in amounts equal to or greater than twenty five percent.
 15. A briquet or other solid fuel composition, comprising: coal having a fixed carbon of 65 percent or more, charcoal, and coke, wherein the coal, charcoal and coke have a combined weight representing from 55 to 90 percent of the total weight of the briquet; and where the coal represents from 50 to 75 percent of the combined weight; and the coke is present in an amount of 2-5 percent of the combined weight; and at least ten percent of at least one alkali metal nitrate, wherein the briquet is characterized as having an ashover time of less than ten minutes and a cooking time of more than ninety minutes.
 16. A briquet or other solid fuel composition system for cooking, comprising: briquets comprising coal, charcoal, coke and two alkali metal nitrates; and an alcohol based gel ignition aid; wherein the system is characterized as having a starting time of less than one minute, an ashover time of less than five minutes and a cooking time of more than two hours.
 17. A briquet or other solid fuel composition, comprising: from 35 to 45 percent by weight coal having a fixed carbon of 65 percent or more, from 16 to 20 percent by weight charcoal, from 4 to 6 percent by weight by weight coke, from 25 to 30 percent by weight barium nitrate, from 4 to 6 percent by weight sodium nitrate, and from 3 to 5 percent by weight starch. 